A typical container-treatment machine receives containers and subjects them all to the same processing steps. Such a container-treatment machine typically receives containers on a conveyor and then passes them to some pre-defined set of treatment sections.
This procedure presupposes that all the containers will require more or less the same treatment. However, this may not always be the case. There may be cases when some containers need different treatment from other containers. For example, heavily-soiled containers may require greater treatment than lightly-soiled containers.